Spacer expander

ABSTRACT

A spacer expander for an internal combustion engine piston ring assembly has a plurality of T-shaped cut-out portions alternating from both side edges so that remaining edge portion forms a plurality of projections between the cut-out portions. Upper pressure areas, vertical outside areas and lower pressure areas, with a plurality of oil passages formed on the outside areas, are formed between the cut-out portions. The projections are curved outwardly at right angles. The upper and lower pressure areas are curved with respect to the vertical outside areas and at right angle to the same sides. The spacer expander is inserted into the piston groove by bending it into circular shape so that the projection side lies to the inside of the groove in such a manner that side rails inserted into the piston groove are mounted on the spacer expander at their projections so that the projections push the side rails in the outward direction in order for the outer peripheral surface of the side rails to slidably contact with the cylinder wall.

United States Patent Matsumoto 51 Apr. 18, 1972 [54] SPACER EXPANDERPrimary Examiner-Samuel B. Rothberg [72] Inventor: Yoshio Matsumoto,Gumma, Japan Atmmey -Sughrue Romwen Mlon zmn & Macpeak [73] Assignee:Nippon Piston Ring Co., Ltd., Tokyo, [57] ABSTRACT Japan A spacerexpander for an internal combustion engine piston [22] Filed: Mar. 16,1970 ring assembly has a plurality of T-shaped cut-out portionsaltemating from both side edges so that remaining edge portion [21]Appl' 19828 forms a plurality of projections between the cut-outportions.

Upper pressure areas, vertical outside areas and lower pres- [30]Foreign Application Priority Data sure areas, with a plurality of oilpassages formed on the outside areas, are formed between the cut-outportions. The pro- Sept. 6, Japan jections are ed out a d y a angles.The pp nd lower pressure areas are curved with respect to the verticaloutside areas and at right angle to the same sides. The spacer [58] g i"5 5 2 202 expander is inserted into the piston groove by bending itinto I circular shape so that the projection side lies to the inside ofthe groove in such a manner that side rails inserted into the [56]References cued piston groove are mounted on the spacer expander attheir UNITED STATES p ATENTS projections so that the projections pushthe side rails in the outward direction in order for the outerperipheral surface of g g-" {:8 the side rails to slidably Contact withthe cylinder wall. ay ew 2 Claims, 3 Drawing Figures P'ATEmEmPR 18 I9723,656,767

INVENTOR YOSHIO MATSUMOTO M W W ATTORNEYS.

SPACER EXPANDER BACKGROUND OF THE INVENTION Field of the Invention Thisinvention relates to a spacer expander for an internal combustion enginepiston ring assembly, and more particularly to an improved simple spacerexpander adapted to provide high resiliency so as to maintain thecontact pressure of the side rails with the cylinder wall constant toincrease the conformability of the same.

, SUMMARY OF THE INVENTION The present invention provides a spacerexpander for an internal combustion engine which is both simple andstrong in structure. The present invention provides a spacer expanderhaving increased flexibility to increase the conforrnability of the siderails with the piston groove to the cylinder wall.

The spacer expander allows high fluidity of oil due to the provision ofoil passages at the vertical outside area thereof.

In particular, the present invention provides a spacer expander which isadapted for use in a piston having a groove for the piston ring ofnarrow width in the axial direction of the groove.

The other features and advantages of the present invention will becomeapparent from the following description taken in conjunction with theaccompanying drawings:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the originalstrip material forming the spacer expander of the present invention;

FIG. 2 is a perspective view of the spacer expander after forming inaccordance with the present invention; and

FIG. 3 is a partial sectional view of a portion of the engine showingthe spacer expander inserted into the groove of the piston incombination with side rails.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to thedrawing, and in particular to FIG. 1, which shows an original flat platefor the spacer expander before forming. The spacer expander for aninternal combustion engine comprises a plurality of cut-out portions 1,of T-shape configuration equidistantly formed, in alternate fashion onboth sides, so that the remaining portions 3 form a plurality ofprojections 2, on both sides and between the cutout portions 1. Upperpressure areas 31, vertical outside areas 32, lower pressure areas 33are formed, and a plurality of oil passages 4 are formed within theoutside areas 32, formed between the cut-out portions 1. The projections2 of the spacer expander are bent outwardly at the line X at rightangles at both sides as shown in FIG. 1. The upper and lower pressureareas 31 and 33 are bent with respect to the vertical outside areas 32at right angles toward the same sides, at lines Y at both sides as shownin FIG. 1. Thus formed, original plate of the spacer expander is cut toa desired length thereof and bent into circular shape such that theprojection side is to the inside. Thereafter, this spacer expander asthus bent is inserted into the groove G of the piston 5 for the pistonring in such a manner that the side rails S also inserted into thegroove of the piston, are mounted on the spacer expander at theprojections 11 on both sides so as to push the side rails at the innerperipheral edges S in an outward direction in order for the outerperipheral edges S of the side rails S to slidably contact the cylinderwall 61 of cylinder 6.

pistoriwithin thec linder.

It rs underst from the foregoing description that the spacer expanderdefined by a plurality of T-shape cut-out portions of the presentinvention is simple and not only strong structurally but is alsoflexible to increase the conformability of the side rails when insertedinto the piston groove to the cylinder wall.

It is also understood that the present invention provides a spacerexpander which maintains good fluidity of the oil by the provision ofthe oil passages at the vertical outside area and is readily adapted foruse with a piston having a groove of narrow width in the axial directionof the piston.

What is claimed is:

1. A spacer expander for an internal combustion engine piston ringassembly comprising:

a thin strip having a plurality of equidistantly spaced T- shapedcut-out portions alternating from both sides thereof, and forming aplurality of projections at both sides between said cut-out portions,said strip being bent between said cut-out portions into substantially aU- shaped crosssectional configuration to further define upper pressureareas, vertical outside areas and lower pressure areas, with saidprojections being bent outwardly at right angles from said upper andlower pressure areas and said upper and lower pressure areas bent atright angles with respect to said vertical outside areas and toward thesame side thereof, said upper and lower pressure areas each comprising aseries of continuous segmented portions, and

a plurality of oil passages within said outside areas between each saidcut-out portion lying in the same vertical plane.

2. A piston ring assembly for a piston reciprocating within a cylinderand having a peripheral groove facing the cylinder wall, said assemblycomprising: 7

a spacer in the form of a thin strip having a plurality of equidistantlyspaced T-shaped cut-out portions alternating from both sides thereof,and forming a plurality of projections at both sides between saidcut-out portions, said strip being bent to further define upper pressureareas, vertical outside areas and lower pressure areas, with saidprojections being bent outwardly at right angles from said upper andlower pressure areas and said upper and lower pressure areas bent atright angles with respect to said vertical outside areas and toward thesame side thereof, said upper and lower pressure areas each comprising aseries of continuous segmented portions, and

a plurality of oil passages formed within said outside areas betweeneach said cut-out portion lying in the same vertical plane, said spacerexpander being inserted into said piston groove by bending it intocircular shape with said projections toward the bottom of said groove,and said side rails inserted within the piston groove and mounted onsaid spacer expander with said projections contacting the innerperipheral surface of respective side rails to push the side railsoutwardly so that the outer peripheral surface of said side railsslidably contact the cylinder wall of the internal combustion engine.

1. A spacer expander for an internal combustion engine piston ringassembly comprising: a thin strip having a plurality of equidistantlyspaced T-shaped cut-out portions alternating from both sides thereof,and forming a plurality of projections at both sides between saidcut-out portions, said strip being bent between said cut-out portionsinto substantially a U-shaped cross-sectional configuration to furtherdefine upper pressure areas, vertical outside areas and lower pressureareas, with said projections being bent outwardly at right angles fromsaid upper and lower pressure areas and said upper and lower pressureareas bent at right angles with respect to said vertical outside areasand toward the same side thereof, said upper and lower pressure areaseach comprising a series of continuous segmented portions, and aplurality of oil passages within said outside areas between each saidcut-out portion lying in the same vertical plane.
 2. A piston ringassembly for a piston reciprocating within a cylinder and having aperipheral groove facing the cylinder wall, said assembly comprising: aspacer in the form of a thin strip having a plurality of equidistantlyspaced T-shaped cut-out portions alternating from both sides thereof,and forming a plurality of projections at both sides between saidcut-out portions, said strip being bent to further define upper pressureareas, vertical outside areas and lower pressure areas, with saidprojections being bent outwardly at right angles from said upper andlower pressure areas and said upper and lower pressure areas bent atright angles with respect to said vertical outside areas and toward thesame side thereof, said upper and lower pressure areas each comprising aseries of continuous segmented portions, and a plurality of oil passagesformed within said outside areas between each said cut-out portion lyingin the same vertical plane, said spacer expander being inserted intosaid piston groove by bending it into circular shape with saidprojections toward the bottom of said groove, and saId side railsinserted within the piston groove and mounted on said spacer expanderwith said projections contacting the inner peripheral surface ofrespective side rails to push the side rails outwardly so that the outerperipheral surface of said side rails slidably contact the cylinder wallof the internal combustion engine.